Challenge Team Abstract
Team Number: 010
School Name: Aztec
Area of Science: Computer Science
Project Title: Encryption
Our project is based off of a previous project by a member of our team. XOR
encryption is an encryption process in which the binary of plaintext is
compared to the binary of a repeating key in which:
1 XOR 1 = 1
0 XOR 0 = 1
1 XOR 0 = 0
0 XOR 1 = 0.
The resulting binary is changed back into ASCII, creating a jumble of symbols and letters.
Previously XOR was decrypted by brute force: the program guessed a password. This process could take considerable amounts of time. Our team's plan is to shorten the time taken by several different procedures.
First: There are printable and non-printable characters. Through mathematical
computation, last year's team was able to conclude that:
Printable XOR Printable = Printable
Non-Printable XOR Non-Printable = Printable
Non-Printable XOR Printable = Non-Printable
Printable XOR Non-Printable = Non-Printable
Since we can assume that the sender would most likely no be using non-printable characters we can filter out half of the possible plaintexts by looking at the results
Second: Our team plans to experiment with binary pattern searching, a process that last year's team didn't have enough time to pursue. By finding a pattern we may be able to assume the length of the key.